Urinary dysfunctions in the lower urinary tract can occur due to detrusor dysfunctions, various sensory bladder disorders, and sphincter dysfunctions. These dysfunctions, in turn, can be divided into storage, voiding, and postmicturition symptoms. The dysfunctions are generally due to overactive or underactive detrusor and/or sphincter.
Dysfunction in the detrusor and sphincter muscles can have multiple causes and a number of different symptoms. Common for all urinary disorders is that the storage phase or the voiding phase of the bladder is affected. When a patient has issues with the storage phase it may appear as urinary incontinence while problems with the voiding phase may lead to urinary retention. Thus, incontinence causes leakage in the storage phase, while retention causes inability to void voluntarily and/or residual urine after voiding. These are the most common urinary disorders.
Urinary retention (UR) is a condition where the urinary bladder is unable to void urine completely. This can be caused by blockages of the urethra, nerve problems, medications, weakened bladder muscles, or as a side effect to treatment of urinary incontinence. Issues that may cause UR include prostate enlargement, vaginal childbirth, brain or spinal cord infections or injuries, diabetes, stroke, MS, pelvic injury or trauma, or heavy metal poisoning.
Urinary incontinence (UI) is the involuntary leakage of urine from the urinary bladder. It is a large and ever growing problem, and it is e.g. expected that most women are affected at some point in their life. Urinary incontinence is generally caused by an underactive sphincter, where it cannot contract properly since the sphincter cannot keep tight and leakage may occur. Reasons for having an underactive sphincter could be complex vaginal deliveries, gynecological surgeries, radiation damages, unsuccessful urological procedures, etc. An overactive sphincter is contracted most of the time which may lead to voiding symptoms, such as urinary retention. Urinary incontinence can also occur due to having an overactive bladder, which is when nerves send signals to the bladder to micturate at the wrong time.
Known treatments or managements for urinary incontinence comprises incontinence products, such as incontinence pads, catheterization products, and surgery.
Many attempts have been made to provide stents and other insertable or implantable products that would be useful for bladder control, to overcome the problems related to UI or UR.
For example, U.S. Pat. No. 5,782,916 discloses a prosthetic device having first anchor means to be arranged in the bladder, and second anchor means to remain in the urethra, and a tubular element with a duck-bill valve. However, this device is intended to drain urine by voluntarily increasing the pressure in the bladder. However, in practice, this would inevitably lead to leakage, when coughing, laughing, lifting heavy loads, exercising, etc.
Further, DE 2537506 is an old example of an implantable prosthetic device, having a magnetic valve, which is operated by an external magnet. However, this device needs to be fixed to the urethra by surgery, making the processes of inserting, removing and replacing the device both costly and potentially hazardous. Further, the valve is difficult to control properly, and would require a very large magnet to work, which is highly unpractical for practicing in daily life.
Still further, U.S. Pat. No. 5,366,506 discloses a urethral magnet valve for placement in the urethra, and which is controllable by an external magnet. However, this product would also be difficult to control properly, and would require the use of very large magnets.
U.S. Pat. No. 5,996,585, finally, discloses a device for housing a valve, and with retention elements to maintain the device in place. However, since the device extends out from the urethra at one end, thereby significantly increasing the risk of urinary tract infections and the like.
A general problem related to such known devices is also that the space available for inserting the device into the urethra, and for housing the valve within the urethra, is very limited. The female urethra is e.g. typically 6-8 mm in diameter, in expanded state, during voiding, which means that the device need to be compressible to such dimensions in order to be able to insert it without surgical procedures, and without causing pain and damage to the patient. Further, arranging a structure also comprising a valve device in the urethra by necessity severely limits the available lumen area for the urine to be drained out. Thus, most of the prior art devices would have insufficient drainage capacity, leading to insufficient drainage, and also a very tedious draining process.
A further general problem with the known devices is that in case of malfunction, it is difficult or even impossible to drain urine out of the bladder. The only solution would often be to remove the device, e.g. with a surgical procedure. This is an expensive and cumbersome procedure. Further, if this is not done relatively quickly, the overfilling of the bladder will cause pain for the patient, and may also be dangerous and life-threatening. For example, there is a risk that urine will flow back into the ureters and damage the kidneys.
There is therefore a need for a new and improved urethral device which addresses these issues, and in particular a urethral device which can be controlled efficiently by the user, thereby providing drainage only at will and alleviating the need of leakage at other times, which is small enough to be inserted in a fast, reliable and painless way, which provides adequate draining flow rate, which can be maintained inserted/implanted for a long period of time, with minimal risk of urinary tract infections and the like, which can be easily emergency drained in case of malfunction, and/or which can be produced and used cost-effectively. In particular, there is a need for such a urethral stent which can be used for women suffering from urinary incontinence due to an underactive sphincter.